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Surat North – Water Monitoring & Management Plan

QGC

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APPENDIX L: FYFE REPORT ON QCLNG PROJECT SOIL SUBSIDENCE MONITORING SURVEY

QCLNG PROJECT

SOIL SUBSIDENCE MONITORING SURVEY

PREPARED BY Fyfe Pty Ltd

ABN 57 008 116 130

ADDRESS 84B Hypatia Street, Chinchilla Qld 4413

CONTACT Craig Scutchings, Survey Manager

TELEPHONE office 61 7 4672 6102

DATE 18/08/2014

©Fyfe Pty Ltd, 2014

Proprietary Information Statement

The information contained in this document produced by Fyfe Pty Ltd is solely for the use of the Client identified on the cover sheet for the purpose for which it has been prepared and Fyfe Pty Ltd undertakes no duty to or accepts any responsibility to any third party who may rely upon this document.

All rights reserved. No section or element of this document may be removed from this document, reproduced, electronically stored or transmitted in any form without the written permission of Fyfe Pty Ltd.

Document Information

Prepared by: MARK SINDERBERRY SITE SUPERVISOR, Fyfe Pty Ltd Date: 17 August, 2014

Approved by: CRAIG SCUTCHINGS SURVEY MANAGER, Fyfe Pty Ltd Date: 18 August, 2014

Revision History

Revision Revision Status Date Prepared Reviewed Approved

A 18/8/2014 MDS CAS


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CONTENTS

Page

EXECUTIVE SUMMARY ii

1. SCOPE OF WORK 1

2. METHODOLOGY 2

2.1 Preparations 2

2.2 Field Work 3

2.3 Collate Data 4

3. RESULTS 5

3.1 Results Table 5

3.2 Result Analysis 6

4. CONCLUSION 7

APPENDICES

Appendix A MONITORING STATION AHD Charts Appendix B Ground Monitoring Maps – (October 2013 to May 2014) Appendix C Ground Monitoring Maps – (October 2013 to August 2014)


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EXECUTIVE SUMMARY

Coal Seam Gas (CSG) mining, undertakes a process whereby it removes associated waters from beneath the

surface, reducing the pressures in the soil formations, which leads to the premise that there may be a degree

of subsidence at the surface.

The Queensland Gas Company (QGC) has a legal obligation to detect any subsidence, and has instigated an

ongoing Soil Subsidence Monitoring Plan, to measure this potential ground movement. Presented in the

following pages, is a report in relation to how this ground monitoring is being measured and results to date.

During the course of background research for this project it was found that a baseline study has already been

conducted over four years (from January 2007 to January 2011), utilising Synthetic Aperture Radar (InSAR), to

give a historic data account of the ground movement, but this data is not shown in and does not represent

any part of this report.


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1. SCOPE OF WORK

Fyfe have been tasked to conduct geodetic surveys on a quarterly basis in order to monitor key permanent

marks in the QGC area of operations, predominately in the Surat Basin. The observations are to be recorded

and presented in a suitable manner to show any trending in the rise or subsidence of the ground surface over

a period of time.


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18/08/2014 PAGE 2

2. METHODOLOGY

Approximately 30 previously coordinated permanent survey marks (PSMs) were supplied to Fyfe as a base to

utilise for observations. The selected marks were chosen to give a good geometry over the area of interest.

These marks were checked for stability, access and repeatability.

Prior to the first round of observations Fyfe suggested the installation of concrete monitoring pillars for use

as the stations for the project. The advantage of having well constructed, deep stable permanent marks like

pillars as the stations is the elimination of seasonal ground heave and swell, elimination of equipment setup

errors and the added ability to site each mark in the best possible location to satisfy the project needs. In the

end, the cost and time associated with the installation of pillars made them uneconomical and existing PSMs

were reverted to as originally planned.

2.1 Preparations

Prior to performing the field work a field reconnaissance was undertaken in order to verify the survey marks

to be used. All equipment was check and calibrated and software updated to suit. A network design was

carried out in order to utilise the resources in the best possible method, and a spreadsheet for results was

established.

2.1.1 Field Reconnaissance

The PSMs supplied to Fyfe for use in the subsidence survey were examined to ensure they were suitable as

high precision monitoring stations. A field reconnaissance was required to check that the marks were

suitable to use. The criterion for suitability was based upon the type of permanent mark and construction

(for stability), having a clear unobstructed line of sight to satellites (sky plot) and good access to the sites

whilst adhering to the QGC Land Access policy. If any of the marks did not adhere to this, alternative marks

were selected in the vicinity, in order to maintain good geometry.

2.1.2 Equipment Preparation

A full review of all equipment was undertaken which included the calibration of tribrachs, bubble centering

and checks for centering errors. A comparison of measuring tapes was completed for consistency of setup

measurements across all sets of equipment. All GPS units were updated with the latest software and survey

styles adjusted to acquire like readings. Units were also checked against a baseline (known survey marks) for

accuracy and performance for geodetic quality measurements.

2.1.3 Network Design and field procedure

A Global Navigation Satellite System (GNSS) network was designed to ensure sufficient static observations

were planned, that gave satisfactory redundancies, to facilitate a network adjustment to be made if required.

This network design exercise helped plan and prepare for the utilisation of resources, time, costs and data

reporting. It allowed for resources to be minimised and timeframes maximised in order to achieve the results


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as required by Survey Practise (SP1) standards. As a result of the network design, crew scheduling and

equipment utilisation was organised and a procedure developed to maintain consistency of measurements

and reporting of results. This design led to the expectation that 3 crews were to be utilised (unless more

became available), using 6 Dual frequency GNSS receivers on each day of observations. The observation

sessions were to be a minimum of 4 hrs each, with up to three sessions per day per crew.

2.1.4 Office Calculations

Observations were recorded in a raw format and then converted to RINEX, to be reduced through the online

GeoScience Australia AUSPOS GPS processing service. This enables a consistent approach to the reduction of

observations and ensures that results would be calculated from precise monitoring stations which were

independent to the area of interest, continually monitored and maintained by the Geosciences Australia

governing body. The results obtained for horizontal, vertical and Positional Uncertainty (PU) measurements

would be recorded against each survey mark for each independent observation. Both the ellipsoidal height

and orthometric height would also be recorded in order to ensure that geoid‐spheroid separation values (N)

would not distort the results. A spreadsheet showing the Easting, Northing, Elevation, PU values and the

deltas, corresponding to these measurements, has been created and will be updated on a quarterly basis

following each monitoring session.

Individual data sets processed through AUSPOS increase with accuracy over time and therefore will have an

initial calculation using the Ultra Rapid or Rapid method using a predicted ephemeris, and then reprocessed

against the precise ephemeris to achieve the best result. It is envisaged that the results using the above

techniques would have a PU of 10‐15 mm in Easting and Northern, and 15‐30 mm in Elevation.

2.2 Field Work

A field procedure was written to standardise the equipment setup, observation methodology and recording

rate. A Static GPS Observation sheet was also created to record field equipment measurements and other

significant details i.e. crew names, dates, equipment, antennas and file names.

The field work utilised one crew in each of the Northern, Central and Southern areas. They observed up to 4

stations per day for 3 consecutive days. Each session was observed for a minimum of 4 hrs on a standard 30

second epoch rate.

To date there have been three surveys conducted in the field, these being October 2013, May 2014 and

August 2014. The frequency of these surveys is scheduled quarterly, however the January 2014 survey was

not completed due to a delay in the approval to proceed. The next survey is due to be completed in

November 2014.


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2.3 Collate Data

Once the data was captured, it was transferred to the office for processing where field observation sheets

were checked against the files, the files were converted to RINEX format, then individually submitted online

using the AUSPOS facility. Resultant reports have been filed and entered into an excel spread sheet. This

spreadsheet has been established to contain all relevant data, and incorporates multiple checks to ensure

that data entry errors were highlighted and removed.

The spreadsheet records the coordinated results from each station, PU values and compares them to past

results in order to determine if there have been any changes. The differential changes in elevation have been

tabulated to allow for the creation of monitoring station charts (Appendix A), which show the vertical

movement at each point. These will be updated as more observations are surveyed and give a better

representation of what is occurring over time. There are also 3 maps (Northern, Central and Southern Areas)

showing the locations of each station and their corresponding elevation change from the initial October

observations. Each set of maps defines the elevation change, and is displayed in Green if the change is

contained within the PU value and Red if the change is outside the PU value, for the latest monitoring

observation. These can be found in Appendix B & C.


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3. RESULTS

Below is a tabulated set of results showing the difference in elevation observations since October 2013.

3.1 Results Table

Station Name October to May October to August

Northern (mm) (mm)

185013 0.018 0.014

185052 0.009 0.032

183995 0.027 0.001

192744 0.008 ‐0.005

183982 0.032 0.028

MK51_K 0.015 0.024

183524 0.007 0.007

183997 new 0.003

178869 New 0.000

185047 ‐0.016 0.002

Central

168624 ‐0.041 ‐0.041

185032 ‐0.019 0.001

BM1221 ‐0.016 ‐0.033

185035 ‐0.002 ‐0.014

178876 0.028 0.016

177500 ‐0.013 0.001

178882 ‐0.010 ‐0.033

158518 New 0.005

Southern

178886 ‐0.020 ‐0.024

176679 new ‐0.011

183487 0.025 0.007

183518 ‐0.022 0.003

183486 0.023 0.001

185981 0.009 0.007

189001 ‐0.007 0.033

61538 ‐0.003 0.001

183519 0.009 ‐0.008

185017 ‐0.011 0.014

CGL1000 0.009 ‐0.035


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3.2 Result Analysis

The initial sets of observations taken in October 2013 have been used as the bench mark from which all

future observations will be compared against. It was initially suggested to use the Department of Natural

Resources and Mines (DNRM) published Form 6 Station elevations as a starting bench mark, as it may have

helped provide historic data. This would be true, however, it was noted that not all monitoring stations were

Permanent Survey Marks (PSM) having a Form 6 submitted. It was also observed that the Class and Order

(which is now referred to as Positional Uncertainty) were different between some of the marks, making them

unviable to use as part of the monitoring survey due to their unknown relative accuracy.

Unfortunately some of the marks initially used in the October 2013 sessions were either destroyed or had

become inaccessible, requiring other monitoring stations in the near vicinity to be found as replacements for

the May 2014 sessions. The Results Table (3.1), displays the word “new” in those rows where these

replacement marks were utilised. These stations will use the May 2014 results as their bench mark. All 29

marks shown in the table (3.1) will be utilised for future observation unless some unforseen damage occurs

to them.

The results of the horizontal observations showed that each set of Easting and Northing coordinates did not

vary greatly between quarterly sessions, and were contained within the PU of each monitoring station. This

seems to indicate that there is not a lot of horizontal movement at these locations. The elevation

observations also indicate minimal change between sessions, but as there are only a small number of

sessions, it is too early to make any solid predictions about their movements. The range of change (mostly

between 0 – 30mm) is expected given the PU values obtained from the AUSPOS processing. There are only a

few results just outside these values and could be possibly contributed to a number of factors including

natural periodic ground movement. Rainfall causes potential swelling of the ground whereas periods of dry

weather may affect the shrinkage. ‘Wetting and drying’ of the ground are expected to occur, due to seasonal

change, therefore constant monitoring over long periods of time is required in order to quantify and

eliminate them from the elevation changes.

At this stage of monitoring, there is not enough evidence to conclude there is any movement of the ground

outside of the expected survey accuracies. For a true analysis of the data to show potential ground

movement, consistent measuring and computations need to be made. These data results prove that a solid

method of measuring has been established and that with continual surveys, the evidence of any ground

movement would be displayed.


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18/08/2014 PAGE 7

4. CONCLUSION

The ground monitoring of specific locations within the QGC tenement area has been conducted in order to

satisfy the federal conditions for potential subsidence due to the mining of coal seam gas. A consistent

process of survey observations has been adopted and the computational results recorded have proven that a

solid procedure has been established. The results of the surveys conducted to date on 29 ground monitoring

stations, within the QGC tenement, have given consistent results and do not highlight any trend in the

movement of the ground during the period October 2013 through to August 2014.

The surveys would need to continue in order to provide enough data for analysis in order to eliminate

seasonal effects, and to provide evidence of potential subsurface movement.

APPENDIX A MONITORING STATION AHD CHARTS

Northern Area – Monitoring Station AHD Charts

WORK IN PROGRESS

WORK IN PROGRESS

265.494265.512 265.508

265.400

265.500

265.600

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 185013 AHD

234.559 234.568

234.591

234.500

234.600

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 185052 AHD

269.495

269.522269.496

269.400

269.500

269.600

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 183995 AHD

272.015272.023

272.010

272.000

272.100

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 192744 AHD

262.517

262.549 262.545

262.500

262.600

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 183982 AHD

287.764 287.779287.788

287.700

287.800

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

MK51_K AHD

310.927310.934 310.934

310.900

311.000

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 183524 AHD269.192 269.195

269.100

269.200

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 183997 AHD

389.736 389.736389.700

389.800

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 178869 AHD

372.905 372.889372.907

372.800

372.900

373.000

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 185047 AHD

Central Area – Monitoring Station AHD Charts

335.077

335.036 335.036

335.000

335.100

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 168624 AHD

319.962319.943

319.963

319.900

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 185032 AHD

306.765 306.749306.732

306.700

306.800

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

BM 1221 AHD

324.840 324.838324.826

324.800

324.900

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 185035 AHD

309.757

309.785309.773

309.700

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 178876 AHD

326.336 326.323326.337

326.300

326.400

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 177500 AHD

317.212 317.202317.179

317.100

317.200

317.300

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 178882 AHD

325.405 325.410

325.400

325.500

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 158518 AHD

Southern Area – Monitoring Station AHD Charts

342.728 342.708 342.704

342.600

342.700

342.800

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 178886 AHD

350.016 350.005

349.900

350.000

350.100

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 176679 AHD

378.440

378.465378.447

378.400

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 183487 AHD

363.296 363.274363.299

363.200

363.300

363.400

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 183518 AHD

371.336

371.359371.337

371.300

371.400

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 183486 AHD

334.653334.662 334.660

334.600

334.700

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 185981 AHD

345.343 345.336

345.376

345.300

345.400

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 189001 AHD

345.543 345.540 345.544

345.500

345.600

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 61538 AHD

329.271 329.280329.263

329.200

329.300

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 183519 AHD

394.718 394.707394.732

394.600

394.700

394.800

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

PSM 185017 AHD

394.841394.850

394.806

394.700

394.800

394.900

Oct 2013

Nov 2013

Dec 2013

Jan 2014

Feb 2014

Mar 2014

Apr 2014

May 2014

Jun 2014

Jul 2014

Aug 2014

CGL1000 AHD

APPENDIX B GROUND MONITORING MAPS – (OCTOBER 2013 TO MAY 2014)

APPENDIX C GROUND MONITORING MAPS – (OCTOBER 2013 TO AUGUST 2014)

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